A disorder which causes lead guitarist heads to swell to an unimaginable size, with a strange substance known as ego. Resulting in him gaining an inability to hear any other instrument in the band, causing a more frequent supply of solo's, shredding, too much treble, too much distortion, also his guitar always being a little louder than everyone else, and eventually being asked to leave as he does your head in.
Also this disorder is incurable. Get some reverb you gimps.
Drummer - Is it just me or did (lead guitarist) just do a 40 minute blues solo?
Bassist - Yeah he totally has Lead Guitar Syndrome